As part of this study, we will be doing additional tests that may help us understand how temozolomide works. First, if there is a tumor sample from a biopsy done in the past, it will be analyzed for an abnormal gene that may be present in lung cancer. Before starting temozolomide, a research blood test will be done to look for the same abnormal gene we are looking for in your tumor sample. Also, before starting temozolomide and every time you have a repeat CT scan, a research blood test will be done to analyze the number of tumor cells in your bloodstream.